1. Field of the Invention
The present invention relates to a linear guide bearing apparatus used in any of various kinds of machines and apparatus, such as a machine tool, robot or measuring instrument.
2. Description of the Background Art
A known linear guide bearing apparatus of this type is shown in, for example, FIG. 12. This linear guide bearing apparatus has an axially extending guide rail 1 and a slider 2 mounted about the guide rail 1 axially movably relative to the guide rail 1.
The guide rail 1 has an axially extending rolling body rolling groove 3 formed in each of two sidewalls thereof. The slider 2 has a rolling body rolling groove 7 formed in the inner surface of each of two legs 4 of a main slider part 2A and facing one of the rolling body rolling grooves 3. A multiplicity of balls B as examples of rolling bodies are placed rollably between the rolling body rolling grooves 3 and 7 facing each other so that the slider 2 may be axially movable on the guide rail 1 relative to it by the rolling of the balls B.
As the slider 2 moves such that, the balls B between the guide rail 1 and the slider 2 roll toward an end of the slider 2. In this situation, in order to continue the axial movement of the slider, there is required a infinite circulation of the balls B.
Therefore, a rolling body passage 8 is so formed as to extend axially through each legs 4 of the main slider part 2A and a substantially U-shaped end cap 5 is secured to each end of the main slider part 2A by a securing member, such as a screw 12, and has a semi-circular curved turning passage 6 connecting the rolling body rolling grooves 3 and 7 and the rolling body passage 8 to thereby form a rolling body infinite circulation raceway.
A lubricant feeding member 15 for feeding a lubricant to the rolling body rolling groove 3 of the guide rail 1 in sliding contact therewith is situated on the outer surface of each end cap 5 and secured to the end of the main slider part 2A with the end cap 5 by e.g. the screw 12.
The lubricant feeding member 15 is of e.g. a porous resin containing the lubricant, has a substantially U-shaped form like the end cap 5 and has a fixing ring 16 fitted in the outer surface of each of its U-shaped end portions to have the screw 12 pass therethrough and a sliding contact portion 17 projecting from the inner surface of each of its U-shaped end portions to make sliding contact with the adjacent rolling body rolling groove 3 of the guide rail 1 to feed the lubricant thereto, as shown in FIG. 13.
The lubricant feeding member 15 has a recess 19 formed approximately in the center of an upper side thereof so that a ring-like shaped pressing member 18 is adopted to be fitted therein. When the pressing member 18 is fitted in the recess 19 and exerts pressure on the top portion of the lubricant feeding member 15 to deform it outwardly along the width of the slider 2, the U-shaped end portions of the lubricant feeding member 15 situated toward its bottom may be deformed inwardly along the width of the slider 2 so that the sliding contact portions 17 presses against the rolling body rolling grooves 3 of the guide rail 1.
In FIG. 12, each symbol 11 denotes a side seal attached to the outer surface of the lubricant feeding member 15 and secured to the end surface of the main slider part 2A with the lubricant feeding member 15 and the end cap 5 via the screws 12. A symbol 10 denotes a tapped hole formed in the end surface of the main slider part 2A for each screw 12, a symbol 13 denotes a grease nipple, and a symbol 14 denotes a hole for inserting each bolt for securing the guide rail 1.
According to the known linear guide bearing apparatus as described, since the thickness A of the pressing member 18 and the fixing ring 16 are larger than the thickness B of the lubricant feeding member 15 (see FIG. 14), in a case that a plurality of lubricant feeding members 15 are put together as shown in FIG. 15, a clearance C is formed between every two adjoining lubricant feeding members 15 and are undesirably likely to allow fine dust, etc to enter the slider 2 therethrough.
Moreover, as the lubricant feeding member 15 is open to its outside and has an exposed outer periphery, there have been occurred undesirably problems that the lubricant on its outer periphery may easily be deteriorated or vaporize, and that the lubricant may not be fed to the rolling body rolling grooves 3 efficiently, and the lubricant may be lost or deteriorated in an accelerated way under the influence of any coolant, organic solvent, etc used when the apparatus is in operation.
Moreover, since the pressing member 18 and the fixing ring 16 for the lubricant feeding member 15 are made of steel or a resin, it is undesirably likely that the pressing member 18 and the fixing ring 16 may be deteriorated by chemicals, coolant, etc. Further, for each one of the lubricant feeding member 15, one pressing member 18 and one fixing ring 16 are required, which lead to increase number of parts, and make complicate to assemble the apparatus.
Further, according to the known linear guide bearing apparatus as described, the side seals 11 sealing the ends of the slider 2 are rubber seals and present difficulty in the complete removal of finely divided foreign matter. Moreover, the heat generated by sliding friction between the side seals 11 and the guide rail 1 and the sliding wear of their lips lower their sealing performance and disable them to exhibit any satisfactory dust-proofing result.